Use Arduino to automate or assist some job.Package that with a very small board or stand-alone chip for the controller, you program it with your Arduino.

If you use some public domain libraries like SD, you are required to keep your software open. But write your own and you can keep your secrets, AVR chips can be locked from practical means of reading the code.

But first, try making things not to be sales products just to learn do and don't of making. Find out what you can do before wasting time dreaming too much. Get up with your code, poor coding limits what can be done more than 99%.

What you can do when adding parts to the controller is enormous. Dozens of sensors and motors are not too much, IR remote is not too much, SD cards are not too much, switching house mains is not too much, even having it call your phone or send web data to a site is not too much... but it all comes at some cost and ability to wire up and code and invent which is up to you. Don't spend big until you can do more than small.

The Atmega 328 at the core of the Arduino has been used in automation etc by professional engineers for this.

Arduino is basically a cheap educational platform that allows you to learn how to use it.

Many years ago embedded systems were developed using boards costing several hundreds.We had to programme them using hex or octal as well.

What you program the chip in doesn't make it special. What the chip does makes it special.

Arduino Uno is a development board that can be used to make end product controllers with.Arduino IDE is the free development software for Arduino boards.

If you already know how to use Arduino there are many things you can produce with it so how you get "basically a cheap educational platform that allows you to learn how to use it." eludes me since learning how to use it is just the start as stated by docs on this site.

Parts are cheaper now and integration more complete than before, it doesn't make these toys much as that's what I call them. They cease to be toys when they're put to work.

You have an idea, you have some skills to realize your idea. You should be able to make some money off that idea. That's the theory and practice in Arduino DIY for a while but I know that many are angered by all the cheap modules and arduino clones on ebay and beyond. There seems to be nothing you can design to have any price advantage over the flood of modules when a module is sold cheaper with free shipping on ebay than the key component featured on the module. Say I design a board featuring ATMEGA328P. The 328P is about $4 each. Then a nano clone costs only $3 -$3.50 so why designing anything?!

Wow, you need to get a different supplier, you're getting scammed if you're paying anywhere near that much at any sort of purchase quantity for manufacturing.

I think it's still possible to sell hardware for a higher price if you can provide better support, etc. as in the examples of Sparkfun/Adafruit but a lot of customers are going to just get the lowest price board and there's no way to compete on price with a lot of this stuff. I can buy a board on eBay for less than it would cost me to mail it to my neighbor. If you can come up with a new product then there is no competition at first but if it's successful enough the clones are soon to come so you have to be constantly innovating.

The 328P is about $4 each. Then a nano clone costs only $3 -$3.50 so why designing anything?!

Futurlec (ships from HK) has been charging $2.20 ea for single DIP 328P's. Shipping is not free but for me so far, about $7. They sell the DIP 1284P for $7 and have a wide chip selection. I've spent about $40 a pop there.

The software should carry the sales price. Don't expect to compete with China selling empty boards.

Futurlec has held that $2.20 ea ($200 for 100) for the DIP 328P-PU since at least 2012. I saw DIPMICRO beat that at the end of last year but didn't get to move on it till too late.

Where you shop and how many you buy is where you get your price. A factory that produces 100,000 to millions of boards is not paying small quantity prices for chips.

How often do we get farmers wanting to automate chicken coops? Enough to show there's likely many more who don't attempt (or even think of attempting) the project. With the right package, some will buy and pay to have it installed right. Just don't be wrong, it had better be tested and work from the start.